2019 Connecticut Quarterly Estimated Tax Payments

The CT Department of Revenue Services (DRS) requires you to make quarterly estimated tax payments for calendar year 2019 if both of the following apply:

you expect to owe at least $1,000 in State of CT income tax for 2019, after subtracting CT tax withholding and credits, and

you expect CT withholding and credits to be less than the smaller of:

90% of the income tax to be shown on your 2019 CT tax return, or

100% of the income tax shown on your 2018 CT tax return (only applies if your 2018 tax return covered 12 months’ otherwise; utilize the 90% test above only). Note: If you were a nonresident or part-year resident of Connecticut in 2018 and you did not have Connecticut-sourced income during 2018, you must use the 90% test above only.

You are not required to make CT estimated tax payments if:

You were a CT resident during the 2018 taxable year and you did not file a 2018 CT income tax return because you had no CT income tax liability, or

You were a nonresident or part-year resident with CT source income during the 2018 taxable year and you did not file a 2018 income tax return because you had no CT income tax liability.

To calculate your State of CT quarterly estimated tax payments, you must estimate your adjusted gross income, deductions, and credits for the calendar year 2019. Form CT 1040-ES includes an Estimated Connecticut Income Tax Worksheet to help you calculate your CT estimated tax payments.

Frequently Asked Questions

1. What are the filing dates for CT quarterly estimated tax payments?

Payment Period

Due Date

January 1 - March 31, 2019

April 15, 2019

April 1 - May 31, 2019

June 17, 2019

June 1 - August 31, 2019

September 16, 2019

September 1 - December 31, 2019

January 15, 2020*

*You do not have to make the payment due January 15, 2020 if you file your 2019 CT tax return by January 31, 2020, and pay the entire balance due with your return.

3. What if I do not pay enough CT income tax in a timely manner for the calendar year 2019?

Generally, if you do not pay enough tax either through withholding or making estimated tax payments, you may be charged interest. Interest is calculated at a rate of 1% per month on the underpayment of tax.